U.S. Pat. No. 4,876,577, Ogura et al, issued Oct. 24, 1989 and U.S. Pat. No. 4,591,258, Nishino et al, issued May 27, 1986, are typical of a number of references showing a cartridge containing a rotatable photoconductive drum with charging and cleaning stations also within the cartridge. The cartridge is received in an image forming apparatus which rotates the drum to bring it past the charging station within the cartridge where an image surface associated with the drum is uniformly charged. An access opening permits imagewise exposure of the charged surface to create an electrostatic image. The electrostatic image is toned by application of toner either from a toning station within the cartridge or through a toning access opening by a toning station located in the image forming apparatus. Each toner image formed by such toning is then transferred to a receiving sheet which is electrostatically held to a portion of the image surface. The receiving sheet is then fed to a fixing device where the image is fixed.
U.S. Pat. No. 4,712,906 to Bothner et al, issued Dec. 15, 1987, shows, in FIG. 1, a color electrophotographic apparatus in which a series of different color toner images carried on an image member are transferred in registration to a receiving sheet carried on the surface of a transfer drum. The transfer drum is rotated to bring the receiving surface of the receiving sheet continually into transfer relation with the image member to superimpose the toner images creating a multicolor image. The receiving sheet is stripped from either the transfer drum or image member and fixed to create a multicolor copy or print. FIG. 8 of that patent also shows a similar approach, generally known in the art, in which a series of different color toner images are transferred in registration to the outside surface of a transfer drum itself to create a multicolor toner image on that surface. The multicolor image is then transferred in a single step to a receiving sheet at a position remote from the image member. This latter approach has a substantial advantage over the more conventional FIG. 1 approach of not having to attach the receiving sheet directly to the surface of the transfer drum. This makes available a larger variety of receiving sheets and greatly reduces the complexity of the transfer drum.
U.S. patent application Ser. No. 07/650,260, McDougal, IMAGE FORMING APPARATUS AND IMAGE MEMBER CARTRIDGE, filed Feb. 4, 1991, shows an image forming apparatus having a transfer drum to which toner images are transferred to form a multicolor image from an image member that is loadable in the apparatus in an image member cartridge. The cartridge is loadable from the top or side of the apparatus to position the image member in contact with the transfer drum. To load from the top the top portion of the apparatus lifts away from the lower part. The transfer drum is driven by the main drive of the apparatus which, in turn, drives the image member through frictional engagement of their outer surfaces, a feature which greatly simplifies the design of the cartridge.
U.S. Pat. No. 4,598,993, Mizutani et al, issued Jul. 8, 1986, shows a common design of an image member cartridge which is loadable in image forming apparatus by sliding the cartridge in a direction parallel to the axis of rotation of the image member. Projections on the cartridge mate with guide surfaces or grooves in the receiving portion of the image forming apparatus to facilitate this type of loading. This general approach to loading image member cartridges is convenient and somewhat simplifies the apparatus itself.